High-speed computational ghost imaging based onauto-encoder network under low sampling rate

2021 ◽  
Author(s):  
Wei Feng ◽  
Xingyu Sun ◽  
Xiuhua Li ◽  
Junhui Gao ◽  
Xiaodong Zhao ◽  
...  
Keyword(s):  
High Speed ◽  
Sampling Rate ◽  
Ghost Imaging

scholarly journals Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes

2021 ◽  
Vol 18 (9) ◽  
pp. 5046
Author(s):  
Wei-Hsun Tai ◽  
Ray-Hsien Tang ◽  
Chen-Fu Huang ◽  
Shin-Liang Lo ◽  
Yu-Chi Sung ◽  
...  
Keyword(s):  
High Speed ◽  
Center Of Mass ◽  
Reaction Force ◽  
Sampling Rate ◽  
Random Order ◽  
Horizontal Distance ◽  
Acute Effects ◽  
Vertical Ground Reaction Force ◽  
Strength And Conditioning ◽  
Peak Knee

The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0.9 years; body mass: 59.3 ± 8.0 kg; height: 1.73 ± 0.07 m) volunteered to participate in the study. Participants were assigned to perform SBJ with and without 4 kg dumbbells in a random order. Kinematic and kinetic data were collected using 10 infrared high-speed motion-capture cameras at a 250 Hz sampling rate and two force platforms at a 1000 Hz sampling rate. A paired t-test was applied to all variables to determine the significance between loading and unloading SBJs. Horizontal distance (p < 0.001), take-off distance (p = 0.001), landing distance (p < 0.001), horizontal velocity of center of mass (CoM; p < 0.001), push time (p < 0.001), vertical impulse (p = 0.003), and peak horizontal and vertical ground reaction force (GRF; p < 0.001, p = 0.017) were significantly greater in loading SBJ than in unloading SBJ. The take-off vertical velocity of CoM (p = 0.001), take-off angle (p < 0.001), peak knee and hip velocity (p < 0.001, p = 0.007), peak ankle and hip moment (p = 0.006, p = 0.011), and peak hip power (p = 0.014) were significantly greater in unloading SBJ than in loading SBJ. Conclusions: Acute enhancement in SBJ performance was observed with handheld loading. The present findings contribute to the understanding of biomechanical differences in SBJ performance with handheld loading and are highly applicable to strength and conditioning training for athletes.

High speed ghost imaging based on a heuristic algorithm and deep learning

2021 ◽  
Author(s):  
Yi-Yi Huang ◽  
Chen Ouyang ◽  
Ke Fang ◽  
Yu-Feng Dong ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Heuristic Algorithm ◽  
High Speed ◽  
Ghost Imaging

High-efficiency fast X-ray imaging detector development at SSRF

2019 ◽  
Vol 26 (5) ◽  
pp. 1631-1637
Author(s):  
Honglan Xie ◽  
Hongxin Luo ◽  
Guohao Du ◽  
Chengqiang Zhao ◽  
Wendong Xu ◽  
...  
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Sampling Rate ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
X Ray ◽  
Temporal Sampling ◽  
X Ray Imaging ◽  
Imaging Detector ◽  
Working Distance

Indirect X-ray imaging detectors consisting of scintillator screens, long-working-distance microscope lenses and scientific high-speed complementary metal-oxide semiconductor (CMOS) cameras are usually used to realize fast X-ray imaging with white-beam synchrotron radiation. However, the detector efficiency is limited by the coupling efficiency of the long-working-distance microscope lenses, which is only about 5%. A long-working-distance microscope lenses system with a large numerical aperture (NA) is designed to increase the coupling efficiency. It offers an NA of 0.5 at 8× magnification. The Mitutoyo long-working-distance microscope lenses system offers an NA of 0.21 at 7.5× magnification. Compared with the Mitutoyo system, the developed long-working-distance microscope lenses system offers about twice the NA and four times the coupling efficiency. In the indirect X-ray imaging detector, a 50 µm-thick LuAG:Ce scintillator matching with the NA, and a high-speed visible-light CMOS FastCAM SAZ Photron camera are used. Test results show that the detector realized fast X-ray imaging with a frame rate of 100000 frames s−1 and fast X-ray microtomography with a temporal sampling rate up to 25 Hz (25 tomograms s−1).

An Encoder Used in an Ultra High-Speed Folding and Interpolating ADC

2014 ◽  
Vol 1049-1050 ◽  
pp. 687-690
Author(s):  
Yu Han Gao ◽  
Ru Zhang Li ◽  
Dong Bing Fu ◽  
Yong Lu Wang ◽  
Zheng Ping Zhang
Keyword(s):  
High Speed ◽  
Binary Code ◽  
Sampling Rate ◽  
Gray Code ◽  
Cmos Technology ◽  
Careful Consideration ◽  
Analog To Digital ◽  
Interleaved Adc ◽  
Time Interleaved ◽  
Error Suppression

High speed encoder is the key element of high speed analog-to-digital converter (ADC). Therefor the type of encoder, the type of code, bubble error suppression and bit synchronization must be taken into careful consideration especially for folding and interpolating ADC. To reduce the bubble error which may resulted from the circuit niose, comparator metastability and other interference, the output of quantizer is first encoded with gray code and then converted to binary code. This high speed encoder is verified in the whole time-interleaved ADC with 0.18 Bi-CMOS technology, the whole ADC can achieve a SNR of 45 dB at the sampling rate of 5GHz and input frequency of 495MHz, meanwhile a bit error rate (BER) of less than 10-16 is ensured by this design.

High Speed Under-Sampling Frequency Measurements on FPGA

2017 ◽  
Vol 7 (3) ◽  
pp. 1316
Author(s):  
Seyed Ehsan Yasrebi Naeini ◽  
Ali Maroosi
Keyword(s):  
Field Programmable Gate Array ◽  
High Speed ◽  
Sampling Rate ◽  
Sampling Frequency ◽  
Phase Changes ◽  
Frequency Measurements ◽  
Frequency Detection ◽  
Field Programmable ◽  
Under Sampling ◽  
Nyquist Rate

A Sampling rate is less than Nyquist rate in some applications because of hardware limitations. Consequently, extensive researches have been conducted on frequency detection from sub-sampled signals. Previous studies on under-sampling frequency measurements have mostly discussed under-sampling frequency detection in theory and suggested possible methods for fast under-sampling frequencies detection. This study examined few suggested methods on Field Programmable Gate Array (FPGA) for fast under-sampling frequencies measurement. Implementation of the suggested methods on FPGA has issues that make them improper for fast data processing. This study tastes and discusses different methods for frequency detection including Least Squares (LS), Direct State Space (DSS), Goertzel filter, Sliding DFT, Phase changes of Fast Furrier Transform (FFT), peak amplitude of FFT to conclude which one from these methods are suitable for fast under-sampling frequencies detection on FPGA. Moreover, our proposed approach for sub-sampling detection from real waveform has less complextity than previous approaches from complex waveform.

Measuring slope-scale crack propagation in weak snowpack layers

2020 ◽  
Author(s):  
Bastian Bergfeld ◽  
Alec van Herwijnen ◽  
Gregoire Bobillier ◽  
Jürg Schweizer
Keyword(s):  
Crack Propagation ◽  
High Speed ◽  
Measurement Techniques ◽  
Sampling Rate ◽  
Visual Observation ◽  
Crack Speed ◽  
Weak Layer ◽  
Failure Initiation ◽  
Mechanical Field ◽  
The One

&lt;p&gt;For a snow avalanche to release, a weak layer has to be buried below a cohesive snow slab. The slab-weak layer configuration must not only allow failure initiation but also crack propagation across a slope. While in the past failure initiation was extensively studied, research focusing on the onset and dynamics of crack propagation only started with the introduction of the Propagation Saw Test (PST), a meter scale fracture mechanical field test. Since then, various studies used particle tracking analysis of high-speed video recordings of PST experiments to gain insight into crack propagation processes and to measure crack propagation speeds. At the slope scale, a few crack speed estimates have been obtained from seismic sensors, videos or visual observation. However, due to experimental limitations, these latter studies can only provide rather crude crack speed estimates and direct comparisons to PST measurements are still missing. Sure, performing experiments in avalanche terrain is challenging and limited for security reasons, but crack propagation occurs also in slopes not sufficiently steep to release an avalanche. This phenomena is called a whumpf. Since crack propagation in whumpfs is presumably similar to that in avalanches, we developed instrumentation to measure crack speeds on artificially triggered whumpfs. We designed small wireless time synchronized accelerometers with a sampling rate of 400 Hz that can be placed on the snowpack. These measure the downward acceleration of the slab when a crack in the weak layer below passes by. Though triggering whumpfs is difficult and unpredictable, we performed a successful experiment with seven sensors placed over a distance of 25 m. Our experiment revealed a crack speed around 50 ms&lt;sup&gt;-1&lt;/sup&gt;. In addition, we obtained very similar crack speed measurements from a 5.3&amp;#160;m long PST carried out close-by (42 ms&lt;sup&gt;-1&lt;/sup&gt;) and a video-based speed estimate of an avalanche triggered two days later (42 &amp;#8211; 55&amp;#160;ms&lt;sup&gt;-1&lt;/sup&gt;). Our unique whumpf measurement is the first slope scale speed value that can be directly compared to results obtained with other speed measurement techniques. The similarity between the measured speeds suggests that the one-dimensional crack propagation in PSTs is also similar to the 2-dimensional crack propagation in Whumpfs and real avalanches. PSTs are therefore well suited to investigate crack propagation processes of dry snow slab avalanches.&lt;/p&gt;

PC104 Interface Recommended for High Speed Data Acquisition Systems

2013 ◽  
Vol 332 ◽  
pp. 119-123
Author(s):  
Dorina Purcaru ◽  
Anca Purcaru
Keyword(s):  
Data Acquisition ◽  
High Speed ◽  
Low Cost ◽  
Sampling Rate ◽  
Signal Acquisition ◽  
Synchronized Sampling ◽  
Data Acquisition Systems ◽  
High Speed Data Acquisition ◽  
High Speed Data ◽  
Energetic Systems

The interface presented in this paper performs a synchronized sampling of all eight common-mode or differential analog inputs with a high sampling rate. This is a low cost interface, entirely controlled by the PC104 CPU. The paper is focused on design and operation aspects of the synchronized analog-to-digital conversion module. This interface is recommended for high speed data acquisition systems and finds its utility in energetic systems, for monitoring the power quality and for recording different specific transient events. Some programmable electronic modules which perform analog and digital signal acquisition in energetic systems already contain a PC104 interface with synchronized sampling of analog inputs; some experimental results are also presented in this paper.

Development of a Transparent Heater to Measure Surface Temperature Fluctuations Under Spray Cooling Conditions

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
A. R. Griffin ◽  
A. Vijayakumar ◽  
R.-H. Chen ◽  
K. B. Sundaram ◽  
L. C. Chow
Keyword(s):  
Surface Temperature ◽  
Indium Tin Oxide ◽  
High Speed ◽  
Quartz Substrate ◽  
Sampling Rate ◽  
Temperature Fluctuations ◽  
Spray Cooling ◽  
Fused Silica ◽  
Measure Surface Temperature ◽  
Lift Off

A heater designed to monitor surface temperature fluctuations during pool boiling and spray cooling experiments while the bubbles are simultaneously being observed has been fabricated and tested. The heat source was a transparent indium tin oxide (ITO) layer commercially deposited on a fused quartz substrate. Four copper-nickel thin film thermocouples (TFTCs) on the heater surface measured the surface temperature, while a thin layer of sapphire or synthetic fused silica provided electrical insulation between the TFTCs and the ITO. The TFTCs were microfabricated using the lift-off process to deposit the nickel and copper metal films. The TFTC elements were 50μm wide and overlapped to form a 25×25μm2 junction. A DAQ program recorded the TFTC voltages at a sampling rate of 50kHz and sent a trigger to a high-speed camera to synchronize bubble images with the surface temperature data. As the bubbles and their contact rings grew over the TFTC junction, correlations between bubble behavior and surface temperature changes were demonstrated.

PC104 Interface Recommended for High Speed Data Acquisition Systems

2013 ◽  
Vol 325-326 ◽  
pp. 926-929 ◽  
Author(s):  
Dorina Purcaru ◽  
Cornelia Gordan ◽  
Romulus Reiz ◽  
Anca Purcaru
Keyword(s):  
Data Acquisition ◽  
High Speed ◽  
Low Cost ◽  
Sampling Rate ◽  
Digital Signal ◽  
Signal Acquisition ◽  
Synchronized Sampling ◽  
Data Acquisition Systems ◽  
High Speed Data Acquisition ◽  
High Speed Data

The interface presented in this paper is recommended for high speed data acquisition systems; it performs a synchronized sampling of all common-mode or differential analog inputs with a high sampling rate. This is a low cost interface, entirely controlled by the PC104 CPU. Programmable electronic modules that contain such PC104 interfaces can be found running in the energetic system from Romania; these dedicated equipments perform the analog and digital signal acquisition for monitoring and recording different specific transient events. Some experimental results obtained using the disturbance monitoring device PC-08/104 are also presented in this paper.

Research on Wideband Guiding System Receiving Technology

2012 ◽  
Vol 214 ◽  
pp. 862-866
Author(s):  
Yong Li Chen ◽  
Shu Yong Lv
Keyword(s):  
Data Acquisition ◽  
Spectrum Analysis ◽  
High Speed ◽  
Main Part ◽  
Sampling Rate ◽  
Data Acquisition System ◽  
High Speed Data Acquisition ◽  
High Speed Data ◽  
Guiding System ◽  
Hardware Circuit

The ultra-high speed data acquisition system is introduced, which has sampling rate of 3GSPS. The design scheme of hardware circuit is given in condition to analyze the theory and technology of signal sampling. The design of the main part circuit is described. The module of serial -parallel conversion and FFT spectrum analysis are designed in software realization. The system has strong commonality because of application of the ADC + FPGA + DSP framework.

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